* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}
.web {
  height: 10000px;
  background-image: linear-gradient(#ffff, #e79e9e);
}
.rocket {
  width: 149px;
  height: 249px;
  background-image: url("../img/rocket_button_up.png");
  position: fixed;
  bottom: 0;
  right: 50px;
  cursor: pointer;
}
.rocket:hover {
  background-position-x: -149px;
}
.rocket-active {
  animation: move infinite 0.2s steps(3, end);
}
@keyframes move {
  from{
    background-position-x: -297px;
  }
  to{
    background-position-x: -743px;
  }
}
